Thermal damage in luminescent solar concentrators (LSC) for photovoltaic systems

The temperature dependence of the optical efficiency of luminescent solar concentrators (LSC) has been studied. It has been found that in the range room temperature (RT) ? 100 °C an important thermal degradation is produced.The damage depends not only on the temperature but also on the nature of the dye and can reach values as high as 37% in the case of RhB.The damage is partially recovered when the LSC is cooled to RT.     

EPR and infrared absorption study in MgO Co-Doped LiNbO3 crystals

In this work the electron spin resonance (ESR) and OH^- infrared absorption spectroscopies have been used in the study of LiNbO₃:Cr³⁺ crystals codoped with MgO. It has been confirmed that the principal defect site at low MgO concentration is the Cr³⁺(Li⁺) centre. For MgO concentration higher than 4%, Cr³⁺ ions located in Nb⁵⁺ site is the dominant centre. The OH^- infrared absorption bands at 2827 nm and 2851 nm are attributed to the OH^--Mg²⁺(Nb⁵⁺) and Cr³⁺(Li⁺)-OH^-- Mg²⁺(Nb⁵⁺) clusters respectively. Evidence supporting this assignment is presented.     

Nd optical multisites in the Ca3(Nb,Ga)2Ga3O12 laser garnet crystal

Laser excited site-selective luminescence of Nd³⁺ ion in the Ca₃(Nb,Ga)₂Ga₃O₁₂ garnet crystal has been investigated for the and transitions. Six main non-equivalent crystal field sites were detected in the garnet. The crystal splitting scheme of the and manifolds was obtained for each Nd³⁺ site. Energy transfer between Nd³⁺ sites was observed by using time resolved spectroscopy.